This invention relates to bumper mounting mechanisms for vehicles and especially to an improved elastomeric energy absorbing unit for automobile bumper systems.
A number of different types of energy absorbing devices have been developed for mounting bumpers on automobiles, in order to absorb energy from an impact on the bumper without transmitting the energy to the vehicle. One type of energy absorber is a common spring. Another type of energy absorber is a shock absorber type of mounting mechanism. A shock absorber has an advantage over a spring, because it has the capability of absorbing a greater amount of impact energy than a spring.
While shock absorber type mounting mechanisms provide good energy absorbing characteristics, they have moving parts and are expensive. Further, they can corrode and lose their effectiveness.
As a less expensive alternative to shock absorbers, some bumper assemblies have been developed with elastomeric energy absorbers, wherein a compressible elastomeric material is used instead of a spring or shock absorber. Elastomeric materials generally are less expensive and involve no moving parts and can provide good energy absorbing characteristics. Typically, such energy absorbers are incorporated in the cavity of a bumper beam and are mounted so that the weight of the bumper beam is carried by the vehicle frame or rail, with the elastomeric material being subject only to compressive forces resulting from impacts on the bumper. Such elastomeric units are designed for specific vehicles and specific bumper assemblies, and a completely new elastomeric unit must be developed for each vehicle. This involves additional time and expense. The necessity of new injection molding dies and the like for each new elastomeric unit increases the cost of these units.
One object of the present invention is to provide an improved elastomeric energy absorbing unit for vehicle bumper assemblies wherein improved energy absorbing characteristics are provided at a low cost.
A further object of the present invention is to provide an efficient energy absorbing unit that can be adapted for use on a wide variety of bumper assemblies in a wide variety of automobiles, thus reducing costs substantially by making it possible to amortize die costs over a larger number of vehicles.